Physiological basis of phototaxis to near-infrared light in Nephotettix cincticeps

• Published in: Journal of Comparative Physiology Vol. 200; no. 6; pp. 527 - 536
• Main Authors: Wakakuwa, Motohiro, Stewart, Finlay, Matsumoto, Yukiko, Matsunaga, Shigeru, Arikawa, Kentaro
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.06.2014; Springer Berlin Heidelberg; Springer Nature B.V
• Subjects: Animal Physiology; Animals; Biomedical and Life Sciences; Butterflies - physiology; Cicadellidae; Color; Color Perception - physiology; Color Perception - radiation effects; Dose-Response Relationship, Radiation; electrophysiology; Hemiptera; in situ hybridization; Life Sciences; Male; Maze Learning - radiation effects; messenger RNA; molecular biology; Nephotettix cincticeps; Nephotettix nigropictus; Neurosciences; ommatidia; opsin; Opsins - classification; Opsins - genetics; Opsins - metabolism; Original Paper; Oryza sativa; Photic Stimulation - methods; Photoreceptor Cells, Invertebrate - metabolism; Photoreceptor Cells, Invertebrate - physiology; Photoreceptor Cells, Invertebrate - radiation effects; phototaxis; receptors; RNA, Messenger; tail; Ultraviolet Rays; wavelengths; Zoology; Ommatidia; Spectral sensitivity; Visual pigment; Phototaxis; Hemipteran insect; Photoreceptor
• ISSN: 0340-7594; 1432-1351
• DOI: 10.1007/s00359-014-0892-4

In a previous study of the phototaxis of green rice leafhoppers, Nephotettix cincticeps (Hemiptera, Cicadellidae), we found positive responses to 735 nm light. Here, we investigated the mechanism underlying this sensitivity to near-infrared light. We first measured the action spectrum using a Y-maze with monochromatic lights from 480 to 740 nm. We thus found that the action spectrum peaks at 520 nm in the tested wavelength range, but that a significant effect is still observed at 740 nm, albeit with a sensitivity 5 log units lower than the peak. Second, we measured the spectral sensitivity of the eye, and found that the sensitivity in the long-wavelength region parallels the behaviorally determined action spectrum. We further identified mRNAs encoding opsins of ultraviolet, blue, and green-absorbing visual pigments, and localized the mRNAs in the ommatidia by in situ hybridization. The electrophysiology, molecular biology and the anatomy of the eye together indicate that the eyes of N. cincticeps do not contain true “red” receptors, but rather that the behavioral response to near-infrared light is mediated by the tail sensitivity of the green receptors in the long-wavelength region of the spectrum.